Lost my Viper key fob alarm is on and cannot start truck. any solution to disable?

Your alarm should have a button that was installed called a valet. What you want to do is put your key in the ignition turn it to the on position (Don't start it) then with the car in the on position hold down the valet button until the led light on the alarm goes solid and you should here the alarm beep twice. now your alarm will be disabled. To reable the alarm do the same thing.

Sounds like you have a starter kill feature on the alarm. You haven't stated which model alarm you have but here is the basic information. You are probably going to need to remove the cover that surrounds the steering column. That should expose the ignition wiring harness. On the newer Viper models, installation requires you to cut the starter wire into. You then wire a green wire from the alarm to the key side of the cut wire and attach a purple alarm wire to the other end of the cut starter wire. This in turn gives the Viper control over the starter wire. If you can bypass this connection then your vehicle should crank.